Antifoam seal for washing machines

ABSTRACT

A WASHING MACHINE IN WHICH ANY FOAM TENDING TO OVERFLOW FROM THE WASHING TUB IS CONVEYED THROUGH CONDUIT MEANS SUCH AS TO PASS THE FOAM THROUGH A WATER BODY IN WHICH IT DISSOLVES.

Sept. 28, 1971 A Z 3,608,339

ANTIFORM SEAL FOR WASHING MACHINES Filed July 11, 1959 3 Sheets-Sheet 1 INVENTOR L amen n ma :2.

ATTORNEYS Sept. 28, 1971 L. MAZZA 3,608,339

ANTIFORM SEAL FOR WASHING MACHINES Filed July 11, 1969 3 Sheets-Sheet 2 INVENTOR Lnhne'lra 070:2. 0

BY 2%w, 1 M,

ATTORNEY;

Sept. 28, 1971 MAZZA ANTIFORM SEAL FOR WASHING MACHINES 3 Sheets-Sheet 5 Filed July 11. 1969 lNVE-NTOR 4. 07 22 States Patent; Office 3,608,339 Patented Sept. 28, 1971 3,608,339 ANTIFOAM SEAL FOR WASHING MACHINES Lamberto Mazza, Pordenone, Italy, assignor to Indusn'ie A. Zanussi S.p.A., Pordenone, Italy Filed July 11, 1969, Ser. No. 841,095 Claims priority, application Italy, Oct. 2, 1968, 21,979/68 Int. Cl. D06f 39/08 US. Cl. 68-208 2 Claims ABSTRACT OF THE DISCLOSURE A washing machine in which any foam tending to overflow from the washing tub is conveyed through conduit means such as to pass the foam through a water body in which it dissolves.

BACKGROUND OF THE INVENTION This invention relates to a device which impedes excess foam formed for any reason during operation of a washing machine from flowing out of the housing of the washing machine and the obvious disadvantages arising therefrom.

This problem is particularly present when a conventional detergent which is not especially suitable for use in washing machines is used for the wash. In fact in these detergents the foam action is not depressed, and following mechanical agitation inside the tank during washing, considerable quantities of foam can be formed in a conventional washing machine, in amounts much greater than the volume of the tank, because of which the foam flows to the outside of the washing machine housing.

The first solution attempted for avoiding this disadvantage was that of hermetically sealing the wash tank.

In this way while eliminating every possibility of outflow of foam, other disadvantages arose of which the main ones were the following:

(1) For adjusting the level of water in the tank pressure switches are currently used whose indication is strictly linked with the compression, by the water entering, of a small and determined volume of air. By sealing the tank hermetically at the moment of loading with water, the air present in the tank is compressed and consequently the indications of the pressure switch are in error.

(2) Water discharge becomes difficult because as the water is discharged, a negative pressure is created inside the tank which hinders this operation.

This invention resolves the problems illustrated briefly above and in particular permits the use of a tank sealed hermetically during washing, by which the outflow of foam is impeded and at the same time it is not subject to the disadvantages mentioned under paragraphs 1 and 2 above set forth.

SUMMARY OF THE INVENTION This object is attained by the antifoam seal of the invention in a washing machine consisting of a wash tank provided with a sealing cover and conventional means with a line interrupter for the introduction of water with or without detergent into the tank, comprising gasket means for the hermetic sealing of the cover; uni-directional valved means downstream of the line interrupter which opens under the action of feed water; tubular means substantially vertical and adjacent to the tank, with the tubular means being open at its lower end and in free communication with the inside of the tank, and connected at its upper end the atmosphere and syphon means having a first extremity in free communication with the internal space of the wash tank and situated above the highest level attainable by the water in the tank and the second extremity arranged inside the tubular means and below the normal level of water in the tank.

In this way, during operation, the wash tank is substantially hermetically sealed and the only open communication is that by way of the syphon means which, however, has its second extremity immersed in the water present in the substantially vertical tube, according to the principle of communicating vessels, because of which the foam which eventually tends to overflow finds itself caused to take a certain path and, in order to flow to the outside, has to pass through the water in which it dissolves.

On the other hand, by suitably adjusting the length of the part of the syphon means immersed in water in the tube, free air communication will exist during water loading between the tank and the outside by way of the syphon means, because of which the air present in the tank will not be compressed until water loading is almost complete and the action of pressure on the pressure switch which controls the water level will be completely overlooked.

Similarly, when water is discharged from the tank, there will be free communication between the tank and the outside after the level has descended below the lower extremity of the syphon tube, because of which a slight negative pressure inside the tank occurs only at the beginning of the discharge and then ceases completely.

The objects and advantages of this invention will be better seen from the description which follows of one preferred embodiment by way of example in which:

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a lateral sectional view of a washing machine including the device according to this invention;

FIG. 2 is a back view, partially in section, of the machine shown in FIG. 1; and

FIG. 3 is an enlarged detailed view of the device ac cording to the invention.

DETAILED DESCRIPTION OF THE DRAWINGS With reference to the drawings, a washing machine is shown which comprises an external housing 10 in which there is a wash tank 11 comprising an upper opening closed by a cover 12 and a bottom discharge opening 13 in communication with a discharge pump 14 having a tube 15 for discharging to the outside. Inside the tank 11, there is a wash basket 16 which rotates around a shaft 17 driven by a motor 18 by way of a conventional transmission mechanism.

A feed pipe 19 is provided for loading with wash water, which receives water from a tube 20 and sends the water by way of the so called line interrupter indicated by a space 21, against a non-return valve 22 loaded by a spring 23, which opens in order to permit the entry of water into a tank 24 for distribution of the detergent, from which the water then enters the Wash tank 11 by way of a pipe 25. A feed pipe 26 also fed by the tube 20 is provided for loading the pre-wash water, to which the detergent is introduced directly together with the washing. A tube 27 rises from the discharge opening 13 of the tank 11 and is substantially vertical, at least at its highest part. The lower end of the tube 27 is in free communication with the tank 11, because of which water attains the same level in the tube 27 during the wash cycle as in the tank '11.

The upper end of the tube 27 opens into a free chamber, of which one part is constituted by the line interrupter 21, and which communicates with the outside by way of a discharge pipe 28 for discharge of possible overflowing water. A hole is formed at a suitable height in the side of the tank 11 in which a tube or syphon 2 9 is sealed, whose extremity 30 is open towards the tank 11 and its other extremity 3-1 is positioned inside the tube 27 so that when water arrives at its maximum level 32 in 'the tank 11' and'hence in the tube 27, the extremity 31 is below the level 32 by a distance denoted H. The approximate length of the distance H for practical applications is about 60 mm. Finally, the cover 12 is provided with sealing gaskets 3 3 which guarantee hermetic sealing of the tank 11 during the wash c'ycle.

The effect of the syphon device described above on the operation of the washing machine is as follows:

(1) During the loading of pre-wash or wash water, and as the level rises in the tank 111, the air present in the tank is expelled by way of the syphon 29, entering the syphon through the extremity 30 and leaving through the extremity 31, and then rising again along the tube 27 before flowing to the outside. When the level passes the lower extremity of the syphon 29, the air is compressed in the upper part of the tank 11 but to such a slight extent as not to influence the indication given by the pressure switch controlling the level.

'(2) .During washing, which is the phase in which the foam is developed, the tank 11 is hermetically sealed and the only passage open is that through the syphon 29 which is obligatory. However, in this case, the foam is compelled to pass through the water column of height H in the tube 27 in order to flow out, and consequently it dissolves in the water.

(3) In the discharge phase, as soon as the water level has descended by the distance H and before a relevant negative pressure has been formed in the head space of the tank, air enters by way of the syphon 29.

It is consequently clear that with the present invention the previously mentioned objects are attained in a simple and economic manner.

It should also be observed that the exit of foam through the water feed pipe is impeded by the non-return valve 22.

The invention has been described with reference to a preferred embodiment, but by way of example only.

'" antifoam seal including tubular means substantially vertical and adjacent to the tank, said tubular means being open at its lower end an in free communication with the inside of said tank at the bottom thereof, and connected at its upper end to the atmosphere and syphon means having a first extremity in free communication with the internal space of the wash tank and situated above the highest level attainable by the water in the tank and a second extremity arranged inside said tubular means and below the normal level of water in said tank.

2. The device as claimed in claim 1, in which said second extremity of said syphon means is located at a distance of about mm. below said normal level of water in said tank.

References Cited UNITED STATES PATENTS 884,522 4/1908 Priestman l37139 909,170 1/ 1909 Eichenlaub 137-247.41X

3,070,984 1/1963 Thomas 68208X 3,159,174 12/1964 Searle et al. 68208X 3,144,759 8/1964 Bochan 68208X RICHARD J. SCANLAN, 111., Primary Examiner US. Cl. X:R. 68196 

